This invention relates to a device for editing and displaying an image provided with digital image processing capability and more particularly to such a device adapted to modify and/or edit input image data such as graphs, photographs and sentences and to thereby display an improved image suitable for a presentation.
At a conference or a lecture, it is common to display image data of all kinds such as graphs, photographs and character arrays for a clearer, more effective presentation. Examples of an optical device commonly used for such a purpose include overhead projectors and slide projectors. With an overhead projector, light from a source lamp is passed through a transparency on which diagrams, characters, etc. are recorded and the transmitted light is directed onto a screen by means of an optical system with a lens and a mirror, thereby producing on the screen an enlarged image of the original input image on the transparency. With a slide projector, a slide is used instead of a transparency and light from a source lamp similarly serves to project its enlarged image on a screen. With such conventional display devices, however, it is extremely time-consuming to prepare an original, be it a transparency or a slide, which will provide a visually attractive image because the original image recorded on the transparency or the slide is directly displayed on the screen without first being edited. For the same reason, a so-called dynamic display whereby the image is moved or changed while it is being displayed cannot be effected by such devices. Although a transparency can be moved on the projection table of an overhead projector or superposed on another transparency while it is being shown and although a figure, a character array, etc. can be drawn on a transparency with a source lamp kept on such that the projected image changes in front of the viewer's eyes, these maneuvers are effected manually and on the spot, and hence predictably good results cannot be expected.
A computer may be used to create an original image to be projected by a large-size projector. With an image display device of this type, however, it is generally difficult to create a program and data for an intended display and it is extremely time-consuming to create an original and since the number of picture elements for the display image is usually limited, only a grainy display will result when the original is projected on a large screen. Moreover, computers which are identical or at least similar to each other must be used for the image editing device for creating and editing an image and the image display device for displaying it. This reduces the independence between the image editing and display devices and limits the freedom of choice in system structure.
The inventors herein have previously considered using image data of edited displays or condensing such data by representing them by symbols and to record them in a non-volatile external memory device such that a desired image can be displayed by reading appropriate image data from such a memory device, but the amount of data per image element which must be recorded is already large and data for operating the display device cannot be included.